I'm firmly in the Xander camp. Ricard would be my 2nd choice if I were on the jury.
Xander, let's not forget, had to survive all those TCs without even a VOTE until all the phrases were spoken in the same challenge. He volunteered to sit out a challenge and stepped up to support Shan's bargaining game with Jeff for rice to feed the whole tribe. 2 things that, regardless of how sincere they were, proved that Xander is ALWAYS calculating, weighing, thinking about leverage. In a word, outwitting.
His ruination of Liana's advantage was both skillful and bold, as was his confidence in not playing his idol for Evvie. He knew that Evvie was safe.
His use of his extra vote was not by accident, nor was it wasted. He took that step as a very aggressive, proactive move, to get Liana out without waiting for a tie and a revote. This gave him cover for his own vote as well, and to me is a decisiveness that shows Xander's determination to "outplay." Voting for Liana before Ricard was the superior move, since Liana was part of the strongest alliance with the most potential jury support.
Xander knew about the Monty Hall problem immediately. His comments in tribal are unwaveringly solid, perfectly calibrated to please all listeners without betraying any personal bias, and delivered in a believably sincere plausibility.
I personally feel that Xander has outwitted, outplayed, and outlasted all the others, to this point, and done so from the bottom, without strong alliances, without a VOTE in half the show, and without playing his idol.
Ricard is smart and strategic, and I will have no complaints should he win. I just feel that Xander's game has been stealthier, under the radar, but no less sharp and aggressive than Ricard's, and all from a place of far less security.